Project Summary The aim of this proposal is to support a novel research program that will allow the integration of behavioral and electrophysiological assays of visual development with modeling of brain development to identify the neural correlates of developmental changes in visual function. We propose to adapt existing methodology of high- density EEG recording for use in an animal model. The goal of the project is to use a non-invasive assay for studying brain development in vivo that will allow direct comparison with behavioral measures of visual function and which will also directly correlate with neurophysiological data obtained through other studies. The resulting data can be directly translated to questions of brain development in humans, and the methodology can be extended to the study of brain maturation in other domains and with other populations. To accomplish our goal, we will develop technology to enable high-density EEG signals to be acquired from infant nonhuman primates. We will generate head models from high-resolution structural MRI scans at a number of developmental stages so that the sources of the EEG signals can be identified across ages. Using the methodology we develop, we will study the development of the major extrastriate visual processing pathways, the dorsal and ventral streams. We will then directly link changes in neural activity to behaviorally measured development of visual function. This project will yield four important outcomes. First, we will obtain the first direct comparison between non-invasively obtained signals reflecting brain development and the development of behavioral visual function. Second, we will provide information on the sources of these signals for direct comparison with single neuron recordings and EEG data obtained in human infants. Third, we will acquire a complete series of developmental brain images that can be used as a normative database in future research. Fourth, we will adapt a very important technology for use in small primates, which will be directly relevant to the problem of evaluation of brain function, for clinical or research purposes, in very premature infants or other small, neurologically challenged individuals.